A conventional drilling tender barge or semi-submersible has a mono-hull with flat bottom. The operability of a drilling tender unit with respect to crane lifting is governed by the vertical motion at crane tip. For a barge, it becomes more challenging to operate in beam seas and quartering seas where the heave motion is coupled with roll motion. The downtime due to waiting on weather in severe weather conditions can be considerably high if the barge experience large roll motions.
Other types of hull designs, such as multi-hull designs have been used in the marine industry. However, these multi-hull designs are mostly used in high-speed ferry craft for its high speed to power ratio advantage, and for boats intended for shallow waters navigation.
It is therefore desirable to provide a drilling tender unit with improved designs that seeks to address at least some of the problems encountered in conventional drilling tender unit, or at least to provide an alternative.